Disintegrating and dispersion apparatus and method



p 8, 1959 I c. A. RIETZ 2,903,191

\ DISINTEGRATING AND DISPERSION APPARATUS AND METHOD Filed Jan. 21, 1955 Z-Sheets-Sheet 1 INVENTOR. far/ A. Q/sfz Arrow/Ev:

p 8, 1959 c. A. mm 2,903,191,

DISINTEGRATING AND DISPERSION APPARATUS AND METHOD Filed Jan, 21, 1955 2 Sheets-Sheet 2 /&

F'IE E INVENTOR. Car/ 1 7. rQ/ezz ATTORNE V5 ilnited States Patent DISINTEGRATING AND DISPERSION APPARATUS AND METHOD Carl A. Rietz, San Francisco, Calif., assignor to Rietz Manufacturing Company, Santa Rosa, Calif., 21 corporation of California Application January 21, 1955, Serial No. 483,394

2 Claims. (Cl. 241-21) This invention relates generally to the wet grinding of various solid materials, and in particular pertains to a method and apparatus for such operations.

In many processing operations it is necessary to reduce solid materials to varying degrees of particle fineness. In conjunction with such grinding or milling operations, one or more components of the solid may be dissolved or dispersed in the liquid medium, or one or more chemical reactions may occur. The liquid medium may, for example, be water, a liquid solvent, or a chemical solution. In many instances prevailing methods and apparatus for this purpose are not entirely satisfactory. Equipment commonly used in the metallurgical industry for Wet grinding operations employs a mill of the ball type connected in closed circuit with a classifier. In the chemical industry it is relatively common to use a crushing or grinding mill in closed circuit with a separate tank provided with an agitator or a mixer. Such equipment is generally designed for specific purposes and therefore is not applicable to a Wide variety of services. In addition the capacity of a given installation is limited.

It is an object of the invention to provide improved process and apparatus for wet grinding operations which will greatly facilitate its installation and use in a wide variety of grinding operations. 7

It is a further object of the present invention to provide a process and apparatus of the above character making possible improved operation and performance, with reference particularly to capacity for a given size of equipment and reduction of the solid material to the desired particle size.

Additional objects and features of the invention will appear from the following description in which the preferred embodiment has been set forth in detail in conjunction with the accompanying drawing.

Figure 1 is a side elevational view in section illustrating complete apparatus incorporating the present invention.

Figure 2 is a side elevational view in section illustrating disintegrating apparatus suitable for use with the apparatus of Figure 1.

Figure 3 is a cross sectional detail taken along the line 33 of Figure 2.

The apparatus illustrated in Figure 1 consists of a closed tank or vessel 10 which is adapted to contain the material undergoing treatment. A disintegrator 12 of the rotary hammer type is shown mounted upon an upper wall of the tank 10, and has its lower portion 11 disposed well within the same. As will be presently explained the lower portion 11 includes an overhung rotor of the hammer type and a sizing screen surrounding the rotor. Other working parts of the disintegrator, include the driving motor, the journals for the rotor shaft, and means for feeding material to the zone of operation of the disintegrator, are located exterior of the tank.

Figure 2 illustrates a suitable type of disintegrator. It consists of a main body 13 which can be in the form of a casting, and which is provided with the base flange 14. It is this flange which is attached by bolts or other suitable means to a complementary flange 16 provided on the tank. A second body part 17 is mounted upon part 13, and serves to mount the electrical driving motor 18. The motor is directly coupled to a vertical shaft 19, which is carried by the journals 20 and 21, and which extends down into the tank, where it mounts the rotor 22.

In a construction illustrated the rotor includes the hammers 23 which are attached to the rotor hub and which are arranged in vertically spaced rows, with the hammers of each row being circumferentially spaced. The screen 24 is essentially cylindrical and is disposed to surround the zone of operation of the hammer 23. The lower end of this screen can be carried by a mounting ring 26, which in turn is attached to the rigid support struts 27. These struts extend vertically and are attached to the base flange 14. The mounting ring 26 "provides an opening for the free discharge of material as outwardly turned abutting ends.

hereinafter described.

The screen 24 can be conveniently made of a strip of suitable material bent to cylindrical form and having The ends are held together by suitable means such as the clamp 29.

The space 41 immediately above the zone of operation of the rotor, can be referred to as a feed space, and serves to receive the material to be treated. In Figure 2 ,this space is in communication with the feed pipe 42 by means of which material can be supplied continuously or intermittently. In the arrangement shown in Figure l the space 41 also connects with the feeder 43 which can be of the feed screw type, and which can serve for the introduction of solid material.

.tion as will be presently described. In Figure 1 pipe line 44 is shown for supplying a liquid feed material to the disintegrator, which can be either a liquid or a liquid together with one or more solids. Pipe line 47, which is shown provided with pumping means 48 can be used for taking the material from the lower portion of the tank 10 and delivering it into the disintegrator. Pipeline 49 is shown for withdrawing material from the tank, either intermittently or continuously.

In operating the apparatus of Figure 1 solid material and liquid are supplied to the disintegrator, either as a mixed stream, or as separate streams of liquid and solids. Within the zone of disintegration the feed is acted upon by the hammers 23 to effect a reduction in particle size by impact, and for simultaneously commingling the solids with the liquid. As long as the feed is continued a mixture of solids and liquid is discharged through the sizing screen 24 to have substantially free flight directly into the interior of the tank 10. Any solids which do not pass through the screen 24 are freely discharged through the opening in the annular ring 26 to drop to the bottom of the tank 10. Figure 1 illustrates a quantity 51 of this material collected in the lower part of the tank. Assuming that it is not to be further processed, it can be drawn off from the tank continuously or intermittently. In many operations, however, it is desirable to continuously recirculate this material through the disintegrator for retreatment, thus progressively reducing the average particle size of the solids. If such retreatment is desired, it is possible to first feed the material through the disintegrator and permit the discharged material to collect in the bottom of the tank, and thereafter for a predetermined period of time, continuously recirculate material by way of pipe 47. Thereafter the completely processed material can be withdrawn through the pipe 49. Instead of operating by such a batch method, feed material can be supplied con- Patented Sept. 8, 1959.

tinuously to the system by way of pipe 44 and the feed means 43, and material continuously recirculated by way of pipe 47. After the desired condition of the material in tank has been attained, continuous withdrawal can be established by way of pipe49.

As previously stated my method and apparatus can be used for a variety of operations where wet grinding of solids is involved. The solid material may be completely insoluble in the liquid medium, in which event the grinding may be carried out to the extent of forming a wet slurry, a suspension of finely divided solids in the liquid, or a colloidal solution, depending upon the extent of fineness developed and the character of the solid and the liquid media. In other instances the solid may contain one or more soluble components which are dissolved in the liquid material during treatment. In some instances all of the solid may be soluble, in which event the process serves to progressively reduce the particle size of the solid and simultaneously cause it to be dissolved in the liquid medium.

One advantage of the present process and apparatus is that it can be carried under completely closed conditions. Thus the atmosphere can be excluded by complete sealing of the tank 10, and by excluding undesired gases from the feedpipe 44 and the feed means 43.

In general my apparatus has high capacity for a given size of equipment. Thus it effects a saving in floor space and reduces the time required for various wet grinding operations.

Although'in the foregoing description I have made particular reference to liquids and solids, the apparatus can be used in some instances for dispersing one liquid in another, either with or without solid material, or for dispersing gases in liquids with or Without the presence of solids.

In many instances it is satisfactory to operate at atmospheric pressure. However by the use of pressure sealing means for the various feed and flow connections, the apparatus can be operated at pressures above atmospheric or at subatmospheric pressures, depending upon the conditions desired.

I claim:

1. In apparatus for the wet grinding of solids wherein a desired intermixture of classified and unclassified solids in a liquid can be obtained: an enlarged substantially closed vessel, a disintegrator mounted upon an upper wall of the vessel so as to extend below said upper Wall, said disintegrator including a rotor of the hammer type mounted upon a vertical axis to thereby form a zone of operation extending down into an upper portion of said vessel, said rotor being journaled at its upper end so as to provide substantially free egress to impacted feed material downward and outward from said zone of operation, said disintegrator also including a generally cylindrical sizing screen surrounding said zone of operation, said screen defining an inlet at the top of said zone of operation and an outlet at the bottom, areas adjacent the outer surface of said screen being in free communication with upper portions of said vessel, feed means expesed exteriorally of said vessel for supplying a feed of wet solids to the top inlet defined by said screen, and means including a pump for returning intermixed solids and liquids from a lower portion of said vessel to said feed means, whereby disintegrated portions of the feed subjected to the impacting action of the rotor are discharged through the classifying screen to fall in free flight with unscreened portions of the feed into the upper portion of said closed vessel.

2. In a method for the wet grinding of solids making use of a substantially closed mixing zone, the step of supplying a feed of intermixed liquid and solid material, repeatedly impacting the solid material so as to cause a disintegrated portion thereof to pass through a classifying medium and to have substantially free flight directly into an upper portion of said mixing zone, permitting impacted solids not passing through said classifying medium to also be freely discharged into an upper portion of said mixing zone, and continuously returning the solids and liquid from the mixing zone to the zone of impacting to thereby progressively achieve a desired intermixture of classified and unclassified disintegrated solids in the liquid.

References Cited in the file of this patent UNITED STATES PATENTS 1,182,432 Stobie May 9, 1916 1,839,513 Weckbaugh Jan. 5, 1932 2,042,880 Cornell June 2, 1936 2,140,076 Fromm Dec. 13, 1938 2,240,213 Fromm Apr. 29, 1941 2,333,246 Harris Nov. 2, 1943 2,435,884 Galewski Feb. 10, 1948 2,543,599 Rietz Feb. 27, 1951 FOREIGN PATENTS 97,630 Switzerland Apr. 2, 1923 1,030,118 France Mar. 11, 1953 

